1. Field of the Invention
The present invention relates generally to hand tools, and particularly relates to extensible handles for ratchet wrenches and similar tools.
2. Description of the Prior Art
It is known to provide an extensible handle for ratchet wrenches and similar tools having a elongated shank, in order to permit the operator to increase the amount of torque exerted during the use of the tool. Examples of prior art extensible handles are discussed in the following patents:
Carlberg, in U.S. Pat. No. 2,382,291, discloses an extensible hand tool having a handle member with a tool-engaging shank slidable into and out of the handle member, with the handle member having an enclosed rearward end. A detent mechanism is provided in the Carlberg device for permitting the shank to be located at different positions along the path of travel.
Condor, U.S. Pat. No. 2,438,633, likewise discloses a shank extensible into and out of a handle member. A spring loaded projection in a hole along the periphery of the shank restricts the extreme outward movement of the shank from the handle member.
Prichard, in U.S. Pat. No. 2,869,410, also discloses an extensible ratchet wrench handle with an enlosed rearward end.
Jeannotte, in U.S. Pat. No. 4,070,932, discloses an extensible handle for a tool headpiece, in which the extension member is operated by a coil spring at the forward end of the tool shank. Like the references disclosed above, Jeannotte teaches a handle member having an enclosed rearward end.
Gentry, in U.S. Pat. No. 4,307,634, discloses a telescoping nut driver with the rearward end of the handle member closed, and with various locking features extending through the side periphery of the handle member into the shank.
Newby et al., in U.S. Pat. No. 4,376,397, disclose a drive mechanism including a detent and a restricting pin along the periphery of the shank to restrict outward movement of the shank.
Potter et al., in U.S. Pat. No.4,440,517, disclose an adjustable torque-multiplier breaker bar assembly with an open rearward end which is attached to a rod with a handle at its rearward extremity in order to provide greater torque.
Other prior art of interest is found in Class 81, subclasses 60 and 177 in the search records of the United States Patent and Trademark Office.